---
name: "CURLOPT_INFILESIZE"
section: "3"
platform: "linux"
package: "curl"
version: "8.23.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/CURLOPT_INFILESIZE"
---

# CURLOPT\_INFILESIZE(3)

size of the input file to send off

## NAME

CURLOPT\_INFILESIZE - size of the input file to send off

## SYNOPSIS

```
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_INFILESIZE, long filesize);
```

## DESCRIPTION

When uploading a file to a remote site, *filesize* should be used to tell libcurl what the expected size of the input file is. This value must be passed as a long. See also *[CURLOPT\_INFILESIZE\_LARGE(3)](/CURLOPT_INFILESIZE_LARGE/3.md)* for sending files larger than 2GB.

For uploading using SCP, this option or *[CURLOPT\_INFILESIZE\_LARGE(3)](/CURLOPT_INFILESIZE_LARGE/3.md)* is mandatory.

To unset this value again, set it to -1.

Using *[CURLOPT\_UPLOAD(3)](/CURLOPT_UPLOAD/3.md)* to an HTTP/1.1 server and this value set to -1, makes libcurl do a chunked transfer-encoded upload.

When sending emails using SMTP, this command can be used to specify the optional SIZE parameter for the MAIL FROM command.

This option does not limit how much data libcurl actually sends, as that is controlled entirely by what the read callback returns, but telling one value and sending a different amount may lead to errors.

## DEFAULT

Unset

## PROTOCOLS

This functionality affects all supported protocols

## EXAMPLE

```
#define FILE_SIZE 12345L
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    long uploadsize = FILE_SIZE;
    curl_easy_setopt(curl, CURLOPT_URL,
                     "ftp://example.com/destination.tar.gz");
    curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);
    curl_easy_setopt(curl, CURLOPT_INFILESIZE, uploadsize);
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
```

## HISTORY

SMTP support added in 7.23.0

## AVAILABILITY

Added in curl 7.1

## RETURN VALUE

*[curl\_easy\_setopt(3)](/curl_easy_setopt/3.md)* returns a CURLcode indicating success or error.

CURLE\_OK (0) means everything was OK, non-zero means an error occurred, see *[libcurl-errors(3)](/libcurl-errors/3.md)*.

## SEE ALSO

[**CURLINFO\_CONTENT\_LENGTH\_UPLOAD\_T**(3)](/CURLINFO_CONTENT_LENGTH_UPLOAD_T/3.md), [**CURLOPT\_INFILESIZE\_LARGE**(3)](/CURLOPT_INFILESIZE_LARGE/3.md), [**CURLOPT\_UPLOAD**(3)](/CURLOPT_UPLOAD/3.md)